Rule attachment.



PATENTED JAN 80, 1906.

- LKRALUND.

RULE ATTAGHMENTH AEPLIGATIOIZ FILED JUNE 5.1905.

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RULE ATTACHMENT...

Specification of Letters Patent.

Patented Jan. 30, 1906.

Application filed June 5, 1905. Serial No. 263,688.

T0 00% whom it may concern:

Be it known that 1, JOHN KRALUND, a citizen of the United States, residing in the borough of Brooklyn, in the city and State of New York, have invented a certain new and useful Improvement in Rule Attachments, of which the following is a specification.

My attachment is of a convenient size to be carried in the pocket and may be applied. to common rules without requiring any change in the rule. It is adapted to serve in two ways. One use is its application to the rule-joint at the mid-length of the ordinary folding rule to hold the arms firmly at right angles each to the other, so that the rule thus held by my device can be used as a square. The other use is to serve as a gage by being clamped on either arm of such rule or even to a corresponding narrow rule or yard-stick not folding. When correctly set with any required portion projecting, it may be moved along the edge of any work and determine the position of a mark made by a pencil or other marker held in the obvious manner against its free end.

My attachment is very simple.

The following is a description of what I consider the best means of carrying out the invention.

The accompanying of this specification.

Figure 1 is a view of one face of my attachdrawings form a part ment. Fig. 2 is a section on the line 2 2 of Flg. 1. Fig. 3 1s an edge view, and Fig. 4 1s a corresponding view of the face opposlte to that shown in Fig. 1. Fig. 5 shows my attachment applied on a rule to hold the rulejoint stifily in the required position to allow the rule to serve as a square. Fig. 6 shows my attachment used on one of the ends of the same rule arranged to serve as a gage.

Similar letters of reference indicate corresponding parts in all the figures where they appear. v

A is the main body of an approximately quadrant-shaped plate, having a lip A turned up along a portion of one of its straight-edges and a corresponding lip A along a corresponding portion of the other straight-edge. A rivet A with an excess of length holding a large thin head A considerably above the plane surface of the body, slot at in a middle position, and holes a a near the respective lips complete this part. The inner face of each lip is accurately finished to match to the rectangular cross-section of an arm of a common rule.

B is another approximate quadrant, which I will term a slide. It is smaller than A and is allowed to slide in its interior. It has a lip bent downward along each straightedge, as indicated. by B 13, each having its outer face accurately finished. A stout post B is set near the periphery B of this slide, extending through the slot (1 in the main body, carries a broad flange B adapted to engage the body and hold the slide and body strongly but loosely together. A slot 1) at the mid-width extending like the slot a in radial direction-that is, to and from the angle A -receives the rivet A A and contributes to hold parts A and B and to guide them in the small amount of sliding motion permitted. The knob B extending farther downward. serves as a thumbpiece by which to act on the slide from the under side.

D indicates coils, and D and D" arms, of a spring, which, taking hold of the rivet A and pressing by the smoothly bent ends of its arms on the divergent inner faces of the lips B B urge the part B yieldingly inward toward the central angle. The metal of B is cut at the inner angle to allow liberally for the circular portion of any rule-joint. The holes a and a loosely receive the ordinary pins when such are present in the rule on which the attachment may be used.

The two slots, the slot (L111 the body A, and the slotb in the slideB, corresponding in direction, each is radial to the angle A at the apex of the body. They are thus in a sense in a line; but they do not coincide in position radially. The slot 6 in the slide engages the firmly-fixed rivet A in the body at a point so far removed. from that at which the slot a in the body engages the firmly-set post in B in the slide that these means of guidance insure a reliable holding of the slide in the correct position as it moves inward toward the angle A by the action of the arm D D or as it moves outward by the superior force of the operator imparted through the thumb-piece B. The curved edge A, the periphery, if such it may be called, of the body A affords a good abutment for the fmgers while the thumb is acting on the thumb-piece. These guiding-points, the contact of the rivet A A with the slot 1) and of the post B B with the slot a, also strongly support the slide against only one lip A or A in being applied on one end of a rule to serve as a gage. I esteem it a valuable quality that these guiding means allow a slight yielding. It is in practice only about enough to allow for slight inequalities in the width and form of the arms of the rule.

My attachment so soon as placed in position and released on a rule gently held at an approximately right angle instantly snaps the parts into a correct position with the outer face corresponding with the lips A A which being, as already stated, finished eX- actly true every other inequality is allowed for by the automatic accommodation of the spring and the guiding means.

Modifications may be made without departing from the principle or sacrificing the advantages of the invention.

The knob B may with advantage be widened to present a broader surface to receive the force of the thumb.

Although for general purposes the lips A A? should be at right angles, the attachment may be made for special purposes with these parts at an angle of sixty degrees or various other angles, as may be preferred.

claim as my invention 1. A body-plate with lips arranged angularly in combination with a slide having lips at a similar angle and a spring urging the slide into the angle adapted to serve with a folding rule as herein specified.

2. A body-plate With lips arranged angularly, and a rivet set therein with a raised head in combination with a slide having lips at a similar angle and a post with a raised head and a thumb-piece, each part having a slot mid-spaced between said lips and an actuating-spring all adapted to serve as herein specified.

3. A body-plate with lips arranged angularly in combination with a slide having lips at a similar angle, means for guiding the slide and a spring coiled around the rivet on the body and acting with its equal ends each against the inner face of one of the lips on the slide, adapted to serve as herein specified.

Signed at New York, in the county of New York and State of New York, this 3d day of June, A. D. 1905.

JOHN KRALUN D.

Witnesses:

W. P. BEACH, ELVIRA RAsMUssEN. 

